Charging the camper battery when driving

[vladio]

I'm trying to wrap my head around this one. We just finished up a weekend at a campground about 3 1/2 hours away. When we're pulling out, I switch the fridge over to 12v to keep it cold. I had the hitch installed at U-Haul and they wanted extra to run 12v back to the plug. The first camper we had didn't need power so i opted out. When we bought the bigger, newer pop up with all the bells and whistles I ran a heavy line off the positive of the battery along with installing a circuit breaker. All's hooked up right and I have power to the plug. After arriving at the campground Thursday, I attempted to raise the roof and could hear, even with the camper plugged in to the shore line and the power inverter doing its best to charge the battery, the battery was low. The roof made it about 3/4 way up and stopped. I used the manual crank and finished it up.

My question is shouldn't the van be powering/charging the camper when we're driving? It seems as though its not wired for this but I'm going to pull the camper info and look into this. I understand that it's risky as it could run down the van battery if we're stopped for a length of time but I can plan around that and use propane if we stop fr a lengthy period.

I look forwar to your input.

Thanks,
Joe

[red31]

Don't forget the other side of the circuit needs to be just as big a wire or bigger. With 5 or 6 function of the 7 blade connector all using the same ground it needs to be as big/bigger than the charge line.

There is no requirement that the fridge run off the PU battery, just a spinning alternator. IDK what the min required voltage at the fridg's 12v terminal block but it should be measured with the tv connected and fridge off and on.

Of course ya gotta start out with a health and charged battery to raise the roof.

[vladio]

RJsfishin wrote:
Maybe you're the one who should learn to read RV language and know that "TV" could and did mean "tow vehicle"
Where did I ever say you wired a camper or television. I'm just thinking ....don't claim to be an experienced elect tech, and then question your own work. If you can't wire something that simple correctly, find someone who can

My post still stands, moron or no moron !!

Do me a favor and chime into someone else's post. I don't need to research your post that added absolutely nothing. Everyone here has attempted to help but you. You chose to act like an arrogant forum lurker that pops into a thread to boost your ego. I never suggested I had a doctorate in electrical engineering but merely stated that I know enough to know what voltage drop is.

There's nothing in anything that I posted where I questioned what I did! This is why I suggest you read and reread that I said I only ran an additional wire where the guys that wired my TV (make u feel better?) didn't. You seem to be fixated on the car audio part and I'm so sorry I mentioned it.

To everyone else:

Thank you all for your input. I did learn from the post and will work more on it next spring. As I have 3 young boys, we tend to keep our trips to 3 hours or less so that's my target for running on 12v. I have the biggest Interstate battery that they offered. I really feel that the RC of the battery along with some charging from my van will be able to keep the fridge cold and leave a little power left over when we arrive.

In the 4 years of being on this forum I've had nothing but good experiences and have tried to offer positive help wherever I can. Yes, sometime I read something that makes me scratch my head but never have I insulted anyone. For the most part, I'd help any of you guys whenever I could.

[TomG2]

".....When we bought the bigger, newer pop up with all the bells and whistles I ran a heavy line off the positive of the battery along with installing a circuit breaker........"

As others have mentioned, it is easy to verify that you are getting a charge from the tow vehicle by comparing the trailer battery voltage unhooked and hooked with the motor running. It should show at least one volt higher. Having said that, and rereading your original post, I would also want to verify that there is a good ground connection between the two units. Just running a line off the + terminal of the battery is only half the connection required.

[Jetta03]

Well that last post was helpful :R

EldIr wrote:
Start the tow vehicle. Should be a big jump in voltage. From the 12.5v range to the high 13's or 14v. If not, the tow vehicle is not providing power to the trailer.

I agree with this. First step is to confirm the battery is receiving a charge with the vehicle running. If this test passes, then consider the size wiring you used from battery to your trailer plug. Here's a sample voltage drop calculation for 20 feet of 10 awg wire, 10 amps of 12volt dc load. I'm guessing at the 10 awg wire, but you can adjust for what you actually used.
Voltage Drop Calculator

That gives about .4 volts drop, enough to have an impact on charging for sure.

[RJsfishin]

Maybe you're the one who should learn to read RV language and know that "TV" could and did mean "tow vehicle"
Where did I ever say you wired a camper or television. I'm just thinking ....don't claim to be an experienced elect tech, and then question your own work. If you can't wire something that simple correctly, find someone who can

My post still stands, moron or no moron !!

[MPD56]

vladio:
My last trailer had a problem similar to yours. There was a 30 amp fuse in the trailer to protect the trailer’s charge wire in case it grounded out. I hooked up a voltmeter to the 12 vdc source of my fridge and didn’t see any change with my TV plugged in or not. I followed the wire till I found the fuse.

[64thunderbolt]

EldIr wrote:

vladio wrote:
What the hell are u talking about? What TV? I ran a wire to the the plug where it wasn't wired by who I had wire the hitch. I didn't wire the camper, did I say I did?

Try fully reading and comprehending a post before you post a smarta$$ comment!

Give me a break.

Yeah, there's a few morons on here you have to ignore. Simple test - connect the trailer plug to the tow vehicle. Read the voltage at the trailer battery with the tow vehicle not running. Start the tow vehicle. Should be a big jump in voltage. From the 12.5v range to the high 13's or 14v. If not, the tow vehicle is not providing power to the trailer.

If it's like my oem tow pkg it will not have power with the tv off. It protects the tv batt from being run down by the TT. Power comes from the charge circuit.

[EldIr]

vladio wrote:
What the hell are u talking about? What TV? I ran a wire to the the plug where it wasn't wired by who I had wire the hitch. I didn't wire the camper, did I say I did?

Try fully reading and comprehending a post before you post a smarta$$ comment!

Give me a break.

Yeah, there's a few morons on here you have to ignore. Simple test - connect the trailer plug to the tow vehicle. Read the voltage at the trailer battery with the tow vehicle not running. Start the tow vehicle. Should be a big jump in voltage. From the 12.5v range to the high 13's or 14v. If not, the tow vehicle is not providing power to the trailer.

[64thunderbolt]

On my truck the supply to the trailer is only hot when the eng is running to prevent running down the truck Batt. Not a lot of power there. Almost like a tender. Not enough to power a 12v fridge.

[vladio]

What the hell are u talking about? What TV? I ran a wire to the the plug where it wasn't wired by who I had wire the hitch. I didn't wire the camper, did I say I did?

Try fully reading and comprehending a post before you post a smarta$$ comment!

Give me a break.

[McZippie]

FWIW upgrade to an Engle .5 to 2.7 amp, 12 volt
Auto switch between 12 and 120 volts.

https://www.engel-usa.com/products/fridge-freezers?p=2

[RJsfishin]

1) You used to wire hi power stereo amps, and you wired the TV in question, but you don't think its wired right ?? What can we say ??

2) Under normal conditions, TT rv'ers have a hard time getting 10-20 amps back to the RV battery, and you turn a fridge on that burns 10-20 amps, and expect what ???
Give us a break !

[vladio]

It's a 120 watt heating element - 10 amps. Running with it off for 3-4 hours causes the temp to rise a lot more than 2-3 degrees which is why I try to run it. This is with cold, pre chilled items inside and the fridge pre chilled for a night prior to loading and leaving. Ill play around with it next year a little. I understand the voltage drop - I used to build car audio systems in the 80's. when I wired this I used the heavy stuff that is used for high end audio amps with heavy draw. I just don't think it's wired right.

Thai u for the input. My sons football season brought a premature end to our camping season. 😞

[rexlion]

Adding solar panels to the roof and a solar controller would supplement your battery charging substantially, assuming you are driving in sunshine. Probably $300 would fix you up.

I was able to stop the fridge from blowing out by adding some home furnace filter material just inside the hatch. Kept blowing out a lot if the wind was the wrong way while driving, but now it stays lit.